I'm getting a chance to take the piston off Wednesday, as I'll be home with the circlip pliers. However, looking ahead to the connecting rods, the Clymer says I'll need some "12-point special male socket?" The only 12-point I can find is a Toyota 1/2in:

I'll try to post decent pictures of the block damage tomorrow.

I got a set of 4 at a box auto parts store for like $6. I only needed the one size. They are a solid 1/2" (I think) hex shank about 3" long with the 12 point male tip. I hot glued one into a junky 1/2" x 3/8" drive socket and there is my tool.

Look for a place that has the Lisle selection of special tools. Good quality and not too costly.

Do not throw the bolts away, you will need them. But mark them so they cannot be mixed up with new ones. They will never run in the engine again but you use them for your measurements. Put the new ones on the tentative shopping list along with the gaskets.

That list is going to tell you the cost of some things, even if you buy nothing. Like the cost in parts just to R&R top end and rods. If you abandon the motor and get another, you can adjust the price of the one you are buying if you know the cost of, for example, checking the top end and rods.